AQA A-Level Philosophy (7172)

## Learning Outcomes

- Explain what functionalism claims about mental states
- Identify how functionalism defines a mental state through inputs, outputs, and relations to other mental states
- Understand why multiple realisability supports functionalism
- Distinguish functionalism from philosophical behaviourism and mind-brain type identity theory
- Explain machine-state functionalism and Putnam’s contribution
- Analyse major criticisms of functionalism, including inverted qualia and absent qualia
- Develop a clear evaluative judgement about whether functionalism gives an adequate theory of mind

## AQA A-Level Philosophy (7172) Syllabus

For the AQA A-Level Philosophy (7172), you are expected to understand functionalism within metaphysics of mind, with a focus on the following syllabus points:

- Know that functionalism claims all mental states can be characterised in terms of functional roles
- Identify functional role in terms of inputs, outputs, and relations to other mental states
- Explain multiple realisability and why it supports functionalism
- Understand the difference between functionalism, philosophical behaviourism, and mind-brain type identity theory
- Know the basic idea of machine-state functionalism associated with Putnam
- Explain the possibility of a functional duplicate with different qualia, shown by inverted qualia
- Explain the possibility of a functional duplicate with no mentality or qualia, shown by Ned Block’s China thought experiment
- Assess whether functionalism can explain consciousness as well as behaviour and mental organisation

## Test Your Knowledge

_Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, look more closely at that area during your revision._

1. What does functionalism claim makes a state mental?
2. How does multiple realisability challenge mind-brain type identity theory?
3. Why is functionalism stronger than philosophical behaviourism?
4. What is the inverted qualia objection?
5. How does Ned Block’s China thought experiment criticise functionalism?

## Introduction

Functionalism is one of the main theories you need to know in the AQA metaphysics of mind topic. It tries to explain mental states without treating them as non-physical substances, but it also avoids reducing them to mere behaviour or to one specific brain-state type. This makes it attractive because it seems flexible and scientifically serious.

The basic idea is simple but powerful: what makes a state a mental state is not what it is made of, but what it does. For exam purposes, that means a mental state is identified by its **functional role** within a system. Functionalism is often praised for handling different kinds of thinkers well, but it faces serious problems when it tries to explain conscious experience and qualia.

> **Key Term: functionalism**
> The view that mental states are identified by their functional or causal role, rather than by their material composition.

### What functionalism says about mental states

Functionalism says that a mental state is defined by the role it plays in a system of inputs, internal relations, and outputs. A mental state is therefore understood in terms of what typically causes it, how it interacts with other mental states, and what it tends to produce.

Take **pain** as the standard example. Functionalists do not say pain just is crying out, because a person may be in pain and hide it. They also do not say pain just is one specific brain event such as C-fibres firing, because another creature might feel pain with a different physical structure. Instead, pain is the state usually caused by bodily damage, linked to beliefs such as “I am injured” and desires such as “I want this to stop,” and tending to produce withdrawal, avoidance, or distress behaviour.

This matters because it gives a richer account than behaviourism. Behaviourism focuses too heavily on outward behaviour or behavioural dispositions. Functionalism includes internal states and their causal links. So behaviour is evidence of pain, but not the whole story of what pain is.

It also matters because functionalism is less restrictive than type identity theory. Type identity theory says each mental-state type must be identical with one brain-state type. Functionalism rejects that. What matters is the organisation of the state, not one fixed physical material.

> **Key Term: functional role**
> The causal role of a mental state, including what inputs typically cause it, how it relates to other mental states, and what outputs it tends to produce.

A useful exam formula is:

- input
- internal state and its relations to other states
- output

Applied to pain:

- input: tissue damage or injury
- internal relations: belief that something is wrong, desire to escape harm
- output: withdrawal, shouting, guarding the injured area

This is why functionalism is sometimes called a **causal role theory**.

> **Test Tip:** In a 3-mark or 5-mark answer, do not just say “functionalism is about what the mind does.” Spell out the three parts: inputs, outputs, and relations to other mental states.

### Multiple realisability and why it matters

One of the strongest reasons for accepting functionalism is **multiple realisability**. The idea is that the same mental-state type could exist in very different physical systems, so long as the relevant function is preserved.

> **Key Term: multiple realisability**
> The claim that the same type of mental state can be realised in different kinds of physical systems.

Suppose a human, a dog, and an alien all feel pain. If pain were identical to one human neural state, then only beings with that exact neural structure could feel pain. That seems too narrow. A dog may have pain even if its brain is not exactly like ours. An alien might also be capable of pain if it has a system that responds to damage, forms avoidance tendencies, and changes its internal processing in the right way.

This gives functionalism a major advantage over **mind-brain type identity theory**. Type identity theory says mental states are ontologically identical with specific brain-state types. Functionalism says this misses the more general pattern. Pain is a role that may be filled by different physical states in different organisms.

Multiple realisability also creates a problem for **philosophical behaviourism**. Behaviourism tries to analyse mental states in terms of behaviour or behavioural dispositions. But there may be no single behavioural pattern that always goes with a mental state. A stoic person may feel pain without showing it. Someone else may cry out at once. The same state can exist with different behaviour. That suggests behaviour is not enough.

Functionalism therefore occupies a middle position:

- against behaviourism, it says inner causal states matter
- against type identity theory, it says no one physical state is essential

This is a major reason why functionalism became influential. It promises a theory of mind that is broad enough to include different possible thinkers while remaining systematic.

### Putnam and machine-state functionalism

Hilary Putnam is strongly associated with **machine-state functionalism**. This version uses the model of a machine, especially a Turing-style machine, to explain how mental states work. The comparison should be handled carefully in the exam: the claim is not simply that the mind is a computer, but that mental states can be understood by analogy with machine states defined by their place in a pattern of state-transitions.

> **Key Term: machine-state functionalism**
> The view that mental states are like machine states, identified by their place in a system of inputs, outputs, and transitions to other internal states.

A machine can be in one state, receive an input, move to another state, and produce an output. Putnam suggests mental life can be understood in a similar way.

For example:

- input: touching a hot surface
- current state: normal alert state
- next mental state: pain
- output: remove hand, form desire to avoid further contact

The important point is that the state is identified by its role in the system, not by the substance realising it. A silicon system, a biological brain, or some other structure might realise the same functional pattern.

This makes machine-state functionalism attractive because it seems to match scientific thinking. It allows us to explain mental organisation without saying that only one biological arrangement can have a mind.

However, do not overstate this. For AQA, the safest phrasing is that functionalism models mental states in terms of causal roles. You do not need to argue that minds literally are computers.

> **Test Tip:** When comparing theories, make the contrast explicit. Behaviourism reduces mind to behaviour. Type identity theory reduces mind to one brain-state type. Functionalism defines mind by causal role and allows different realisers.

### Criticisms: qualia, inverted qualia and absent qualia

The biggest weakness of functionalism is that it seems good at explaining mental organisation but much worse at explaining conscious experience. The issue here is **qualia**.

> **Key Term: qualia**
> The subjective, phenomenal features of experience: what it is like to feel pain, see red, or taste coffee.

The first major objection is **inverted qualia**. Imagine two people who are functionally identical. They classify colours in the same way, stop at red traffic lights, call grass green, and behave exactly alike. Yet one person’s inner experience of red is like the other person’s experience of green. Their functional roles are the same, but their qualia differ.

> **Key Term: inverted qualia**
> The possibility that two functionally identical people could have different qualitative experiences.

If this is possible, then functional role cannot be the whole story of mentality. Two people could match perfectly in input-output structure and internal functional organisation but still differ in conscious experience. That means functionalism leaves something out.

A functionalist might reply that if there is no possible difference in behaviour, judgement, memory, or other internal relations, then talk of different qualia becomes empty. But many philosophers think the inverted qualia case is still conceivable, and that is enough to put pressure on functionalism.

The second objection is even stronger: **absent qualia**. Here the idea is not that two functional duplicates have different experiences, but that one has no experience at all.

Ned Block’s China thought experiment is the standard example. Imagine the population of China organised so that each person plays the role of a neuron in a giant system. They communicate in ways that reproduce the same functional relations as a human brain. If functionalism is true, then this China-sized system should count as having the same mental states as a conscious human being.

> **Key Term: absent qualia**
> The possibility that a system could have the right functional organisation but no conscious experience.
>
> **Key Term: functional duplicate**
> A being or system with the same functional organisation as another, including the same inputs, outputs, and internal state-relations.

Many philosophers find this deeply implausible. They think the system might copy the functional pattern and still lack any real consciousness. If that is right, then functional duplication is not sufficient for mentality.

> **Key Term: Ned Block’s China thought experiment**
> A thought experiment in which a vast organised system duplicates the functional structure of a mind, used to argue that functional organisation may exist without consciousness.

The force of this objection is clear. Functionalism says the right organisation is enough. Block argues that we can imagine the right organisation without genuine mentality. So the theory may explain structure while failing to explain the actual presence of mind.

A related criticism comes from the **Chinese Room**, associated with Searle. A system may produce correct outputs as if it understands language while lacking genuine understanding. This is not always listed as the main AQA objection, but it supports the same line of attack: correct functioning may not equal real mindedness.

The qualia objections together create a serious problem. Functionalism seems strongest when talking about causal organisation and behavioural explanation, but weakest when talking about what conscious states are actually like from the inside.

### How to assess functionalism in a 25-mark answer

A strong essay does not simply list points for and against. It should build a judgement.

Start by defining functionalism accurately. Say that mental states are characterised by functional roles and can be multiply realised. Then explain why that is an advance over behaviourism and type identity theory. This gives the theory genuine appeal and prevents a one-sided essay.

Next, move to the central criticisms. The best route is usually:

1. inverted qualia
2. absent qualia
3. Block’s China thought experiment as support for absent qualia

You can then argue that these criticisms all point to the same deeper weakness: functionalism may explain the causal structure of mental life but not phenomenal consciousness.

A balanced judgement might say that functionalism succeeds as a theory of mental organisation, especially because of multiple realisability, but fails as a full theory of mind if qualia are real and irreducible. If you want a stronger critical line, argue that a theory of mind that cannot explain conscious experience leaves out the most distinctive feature of the mental. If you want a more sympathetic line, argue that qualia-based objections rely on controversial intuitions from thought experiments, while functionalism gives a more systematic and scientifically usable account.

What matters most is justified comparison. Show exactly why functionalism improves on rival theories, and exactly why its critics think that improvement is still not enough.

> **Test Tip:** For AO2 evaluation, avoid saying only “functionalism is wrong because qualia exist.” Explain the argument: if a functional duplicate could have different or no qualia, then functional role is not sufficient to define mental states.

## Key Point Checklist

_This article has covered the following key knowledge points:_

- Functionalism claims mental states are identified by functional or causal role, not by material composition
- A functional role includes inputs, outputs, and relations to other mental states
- Pain is commonly used as the model example: caused by injury, linked to beliefs and desires, and tending to produce avoidance behaviour
- Functionalism is stronger than philosophical behaviourism because it includes internal states, not just behaviour
- Functionalism differs from mind-brain type identity theory because it does not tie one mental-state type to one brain-state type
- Multiple realisability is a major strength of functionalism
- Multiple realisability means the same mental-state type could be realised in humans, animals, aliens, or machines
- Putnam’s machine-state functionalism compares mental states to machine states defined by state-transitions
- Qualia are the subjective features of experience, or what an experience is like
- Inverted qualia suggests two functional duplicates could have different qualitative experiences
- Absent qualia suggests a functional duplicate could have no conscious experience at all
- Ned Block’s China thought experiment aims to show that correct functional organisation may still fail to produce genuine mentality

## Key Terms and Concepts

- functionalism
- functional role
- multiple realisability
- machine-state functionalism
- qualia
- inverted qualia
- absent qualia
- functional duplicate
- Ned Block’s China thought experiment


Metaphysics of mind - Functionalism